Wide color gaut high resolution dmd projection system

ABSTRACT

A wide gamut high resolution projection system has a light source for generating and emitting light, a prism assembly for separating the light into six primary color light beams, and a plurality of digital micromirror device imagers configured to receive and reflect the primary color light beams.

FIELD OF THE INVENTION

The invention relates to a digital micromirror device (DMD) projectionsystem. In particular, the invention relates to a wide color gamut highresolution DMD projection system.

BACKGROUND OF THE INVENTION

With the advent of digital micromirror devices (DMD devices) such asdigital light processors (DLPS) there has been a desire to integrate thedigital projection technology into cinematic theatres for viewing by thepublic at large. However, as of yet, DMDs (and DLPs in particular) havenot yet progressed in native resolution capability so as to allow anacceptable image for large venues which complies with industry standardsfor display quality. Particularly, the Society of Motion Picture andTelevision Engineers (SMPTE) promulgates such standards which are wellrespected by the various members of the motion picture industry. Onesuch standard applies to the display of a all of a Digital CinemaDistribution Masters (DCDMs) (digital packages which contains all of thesound, picture, and data elements needed for a show) in review rooms andtheatres. A requirement of the SMPTE standard is that the pixel count ofthe projected image must be at least 2048×1080 (2K×1K). The standardfurther requires that the mesh of pixels (the device structure) must beinvisible/imperceptible when viewed from a reference viewing distance.While many DMD/DLP projectors meet the minimum requirement regardingresolution, those same projectors cannot meet the second requirement ofthe standard since the proper reference viewing distance is small enoughto cause visibility of the mesh of pixels. Therefore, current DMD/DLPprojectors having 2K×1K resolution are not suitable for most commercialtheatres where the viewing distance is small and where to prevent theappearance of the pixel mesh from an appropriate viewing distance, aDMD/DLP projector must have a resolution of about 4K×2K (which is notcurrently commercially available).

Another problem with current projection systems is that the color gamutachieved by typical single projector systems is not as extensive asintended by the director of the film. A common means for improving colorreproduction has been to incorporate a three-color prism assembly withan associated three-chip set of digital micromirror device imagers. Alight beam that enters the three-color prism assembly, in reaction toknown optical coating methods, is selectively reflected or transmitteddepending on the wavelength of the light. Further, known total internalreflection techniques, such as providing a small air gap between prismassembly components, are used to control the reflection of the dividedcomponents of the light beam. After having been separated into threecolor components, each light beam color component is directed to andselectively reflected out of the prism assembly by a digital micromirrordevice imager. Typically, a first digital micromirror device imagerreflects a blue. color component of the light beam, a second digitalmicromirror device imager reflects a green color component of the lightbeam, and a third digital micromirror device imager reflects a red colorcomponent of the light beam. Each digital micromirror device imager maybe individually controlled in a known manner to produce a combined colorimage which is projected from the prism assembly. However, even use ofthe three-color prism assembly does not provide an adequately wide colorgamut for many image projection applications.

It is therefore desirable to develop an improved DMD/DLP projectionsystem.

SUMMARY OF THE INVENTION

A wide color gamut high resolution projection system has a light sourcefor generating and emitting light, a prism assembly for separating thelight into six primary color light beams, and a plurality of digitalmicromirror device imagers configured to receive and reflect the primarycolor light beams.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a high resolution digitalmicromirror device projection system according to an embodiment of thepresent invention;

FIG. 2 is a schematic illustration of a high resolution digitalmicromirror device projection system according to a second embodiment ofthe present invention; and

FIG. 3 is a schematic illustration of a wide color gamut high resolutiondigital micromirror device projection system according to a thirdembodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to FIG. 1 in the drawings, a high resolution DMDprojection system according to an embodiment of the present invention isillustrated. While it is currently thought that a single DMD/DLP imagerhaving resolution of about 2048×1080 (2K×1K) is insufficient foraccurately reproducing an entire frame of motion picture image data ontoa display surface, high resolution DMD projection system 100advantageously utilizes a plurality of commercially available DMD/DLPimagers (each having resolution of about 2K×1K) to accomplish a totalprojected image resolution of about 4K×2K, a result acceptable by SMPTEstandards. To accomplish this, the entire frame of a target displaysurface 104 is divided into four regions, an upper left region 106, alower left region 108, an upper right region 110, and a lower rightregion 112. Region 106 is to be projected onto by DMD/DLP imager 114,region 108 is to be projected onto by DMD/DLP imager 116, region 110 isto be projected onto by DMD/DLP imager 118, and region 112 is to beprojected onto by DMD/DLP imager 120 such that each imager 114, 116,118, 120 projects only a discrete portion of an entire frame of a motionpicture image. In this embodiment, each imager 114, 116, 118, 120 isconfigured to project a substantially equal area of an entire frame of amotion picture image onto the display surface 104. However, it will beappreciated that in alternative embodiments, the imagers may beconfigured to project unequal portions of a motion picture image whilestill providing a high resolution display. Each DMD/DLP imager 114, 116,118, and 120 is substantially similar to known single-imager typeDMD/DLP imagers, but instead of each DMD/DLP imager 114, 116, 118, and120 having a color wheel filter (as known in the art), a single colorwheel filter 122 is used.

In operation, white light or full spectrum light is emitted from a lightsource 124 and is directed through the spinning color wheel filter 122,with guidance from an elliptical reflector 125. Since each DMD/DLPimager 114, 116, 118, and 120 must be supplied with light, the lightexiting the spinning color wheel filter 122 is separated into fourseparate beams or channels of light (ideally identical in intensity andcolor) through the use of light beam splitting prisms. A first lightbeam splitting prism 126 splits the original light beam 128 into two newlight beams 130 and 132. Light beam 130 is directed from prism 126 intoa second light beam splitting prism 134, resulting in light beams 136and 138. Light beam 132 is directed from prism 126 into a third lightbeam splitting prism 140, resulting in light beams 142 and 144. Each oflight beams 136, 138, 142, and 144 are directed into and deliveredthrough optical fibers (or equivalent thereof) 146 to total internalreflection lenses (TIR lenses) 148 associated with DMD/DLP imagers 114,116, 118, and 120, respectively, such that each imager 114, 116, 118,and 120 receives a single beam of light. TIR lenses are known in the artas being suitable for receiving light, directing the received light to aDMD/DLP imager, and finally outputting the light according to an imagesignal of the DMD/DLP imager. However, it will be appreciated that in analternative embodiment, the TIR lenses may be replaced by field lenses.TIR lenses 148 are oriented to direct their output into an arrangementof reflective prisms 150 and optical blocks (or compensation optics) 152so as to forward the four light beams 136, 138, 142, and 144 (orchannels of light) (as altered by DMD/DLP imagers 114, 116, 118, and120) into a projection optics system 154. Projection optics system 154ultimately directs the light beams 136, 138, 142, and 144 onto regions106, 108, 110, and 112, respectively, of the entire frame of the targetdisplay surface 104. The input signals sent from display controllers ofDMD/DLP imagers 114, 116, 118, and 120 to the mirrors of the respectiveDMD/DLP imagers comprise only the data necessary to create the desiredimage to be projected onto the associated regions of display surface104. Further, the received beams of light are manipulated by imagers114, 116, 118, and 120 to carry motion picture image data correspondingto only a discrete portion of an entire motion picture image frame. Itwill be appreciated that in other embodiments of the present invention,more or fewer DLP imagers may be incorporated to achieve a higher orlower overall film screen resolution, respectively.

Referring now to FIG. 2 in the drawings, a high resolution DMDprojection system according to a second embodiment of the presentinvention is illustrated. High resolution DMD projection system 200 issimilar to system 100 in many ways including the fact that itadvantageously utilizes a plurality of commercially available DMD/DLPimagers (each having resolution of about 2K×1K) to accomplish a totalprojected image resolution of about 4K×2K, a result acceptable by SMPTEstandards. To accomplish this, the entire frame of a target displaysurface 204 is divided into four regions, an upper left region 206, alower left region 208, an upper right region 210, and a lower rightregion 212. However, system 200 comprises four three-imager sets 214,216, 218, and 220 each comprising three DMD/DLP imagers 249 (thethree-imager type DMD/DLP imagers being known in the art) instead offour single-imager type imagers (like 114, 116, 118, and 120). Region206 is to be projected onto by DMD/DLP imager set 214, region 208 is tobe projected onto by DMD/DLP imager set 216, region 210 is to beprojected onto by DMD/DLP imager set 218, and region 212 is to beprojected onto by DMD/DLP imager set 220. Since each DMD/DLP imager ofthe three-DMD/DLP imager sets 214, 216, 218, 220 consistentlymanipulates a single color (red, green, or blue) there is no need for acolor wheel filter (as needed in system 100).

In operation, white light or fill spectrum light is emitted from a lightsource 224 with guidance from an elliptical reflector 225. Since eachDMD/DLP imager set 214, 216, 218, and 220 must be. supplied with light,the light exiting the light source 224 is separated into four channelsof light (ideally identical in intensity and color) through the use oflight beam splitting prisms as was similarly provided for in system 100.A first light beam splitting prism 226 splits the original light beam228 into two new light beams 230 and 232. Light beam 230 is directedfrom prism 226 into a second light beam splitting prism 234, resultingin light beams 236 and 238. Light beam 232 is directed from prism 226into a third light beam splitting prism 240, resulting in light beams242 and 244. Each of light beams 236, 238, 242, and 244 are directedinto and delivered through optical fibers (or equivalent thereof) 246 toTIR lens/dichroic prism assemblies 248 associated with DMD/DLP imagersets 214, 216, 218, and 220, respectively. Assemblies 248 are known forsplitting a light beam into three primary color light beams (red, green,and blue). TIR lens/dichroic prism assemblies 248 are known forreceiving light, directing the received light to DMD/DLP imagers 249,and finally outputting the light. However, it will be appreciated thatin an alternative embodiment, the TIR lens portion of the TIRlens/dichroic prism assemblies may be replaced by field lenses.Assemblies 248 are oriented to direct their output into an arrangementof reflective prisms 250 and optical blocks (or compensation optics) 252so as to forward the. four light beams 236, 238,242, and 244 (orchannels of light) (as altered by DMD/DLP imager sets 214, 216, 218, and220) into a projection optics system 254. Projection optics system 254ultimately directs the light beams 236, 238, 242, and 244 onto regions206, 208, 210, and 212, respectively, of the entire frame of the targetdisplay surface 204. The input signals sent from display controllers ofDMD/DLP imager sets 214, 216, 218, and 220 to the mirrors of therespective DMD/DLP imagers comprise only the data necessary to createthe desired image to be projected onto the associated regions of displaysurface 204. It will be appreciated that in other embodiments of thepresent invention, more or fewer DLP imagers may be incorporated toachieve a higher or lower overall projected image resolution,respectively. By incorporating DMD/DLP imager sets 214, 216, 218, and220, so-called rainbow effects (caused in part by the existence of acolor wheel such as color wheel 122) are avoided and a higher level ofcolor control is achieved.

Referring now to FIG. 3 in the drawings, a high resolution DMDprojection system according to a third embodiment of the presentinvention is illustrated. High resolution DMD projection system 300 issubstantially similar to system 200 in many ways including the fact thatit advantageously utilizes a plurality of commercially available DMD/DLPimagers (each having resolution of about 2K×1K) to accomplish a totalprojected image resolution of about 4K×2K, a result acceptable by SMPTEstandards. To accomplish this, the entire frame of a target displaysurface 304 is divided into four regions, an upper left region 306, alower left region 308, an upper right region 310, and a lower rightregion 312. However, system 300 comprises four six-imager-sets 314, 316,318, and 320 each comprising six DMD/DLP imagers 349. Region 306 is tobe projected onto by DMD/DLP imager set 314, region 308 is to beprojected onto by DMD/DLP imager set 316, region 310 is to be projectedonto by DMD/DLP imager set 318, and region 312 is to be projected ontoby DMD/DLP imager set 320. TIR lens/dichroic prism assemblies 348 dividea light beam into six primary color components rather than only three.This is accomplished by introducing 45 degreed dichroics into eachprimary to create six primary color light beam components for deliveryto six digital micromirror device imagers 349, providing a wider colorgamut and greater color control at a given refresh or frame rate. Inthis arrangement, cyan, blue, yellow, green, red, and magenta colorcomponents are directed toward and subsequently reflected from digitalmicromirror device imagers 349. Since each DMD/DLP imager of thesix-imager sets 314, 316, 318, 320 consistently manipulates a singlecolor (cyan, blue, yellow, green, red, or magenta) there is no need fora color wheel filter (as needed in system 100).

In operation, white light or full spectrum light is emitted from a lightsource 324 with guidance from an elliptical reflector 325. Since eachDMD/DLP imager set 314, 316, 318, and 320 must be supplied with light,the light exiting the light source 324 is separated into four beams orchannels of light (ideally identical in intensity and color) through theuse of light beam splitting prisms as was similarly provided for insystem 100. A first light beam splitting prism 326 splits the originallight beam 328 into two new light beams 330 and 332. Light beam 330 isdirected from prism 326 into a second light beam splitting prism 334,resulting in light beams 336 and 338. Light beam 332 is directed fromprism 326 into a third light beam splitting prism 340, resulting inlight beams 342 and 344. Each of light beams 336, 338, 342, and 344 aredirected into and delivered through optical fibers (or equivalentthereof) 346 to TIR lens/dichroic prism assemblies 348 associated withDMD/DLP imager sets 314, 316, 318, and 320, respectively. TIR lens/dichroic prism assemblies 348 receive light, direct the received lightto DMD/DLP imagers 349, and finally output the light. However, it willbe appreciated that in an alternative embodiment, the TIR lens portionof the TIR lens / dichroic prism assemblies may be replaced by fieldlenses. Assemblies 348 are oriented to direct their output into anarrangement of reflective prisms 350 and optical blocks (or compensationoptics) 352 so as to forward the four light beams 336, 338, 342, and 344(or channels of light) (as altered by DMD/DLP imager sets 314, 316, 318,and 320) into a projection optics system 354. Projection optics system354 ultimately directs the light beams 336, 338, 342, and 344 ontoregions 306, 308, 310, and 312, respectively, of the entire frame of thetarget display surface 304. The input signals sent from displaycontrollers of DMD/DLP imager sets 314, 316, 318, and 320 to the mirrorsof the respective DMD/DLP imagers comprise only the data necessary tocreate the desired image to be printed in the associated regions ofdisplay surface 304. It will be appreciated that in other embodiments ofthe present invention, more or fewer DLP imagers may be incorporated toachieve a higher or lower overall projected image resolution,respectively. By incorporating six-imager DMD/DLP imager sets 314, 316,318, and 320, so-called rainbow effects (caused in part by the existenceof a color wheel such as color wheel 122) are avoided and a higher levelof color control is achieved. Further, the DMD/DLP imager sets 314, 316,318, and 320 offer a much wider color gamut than the three-imagerDMD/DLP imager sets 214, 216, 218, and 220.

The foregoing illustrates only some of the possibilities for practicingthe invention. Many other embodiments are possible within the scope andspirit of the invention. For example, although a specific embodimentdescribes the system with six primary colors, systems with four orgreater primary colors are also considered embodiments of the invention,with the functional equivalent number of DMD/DLP imagers per set (i.e.,the number of imagers per set will equal the number of primary colors).It is, therefore, intended that the foregoing description be regarded asillustrative rather than limiting, and that the scope of the inventionis given by the appended claims together with their full range ofequivalents.

1. A projection system, comprising: a light source for generating andemitting light; a prism assembly for separating the light into sixprimary color light beams; a plurality of digital micromirror deviceimagers configured to receive and reflect the primary color light beams.2. The projection system according to claim 1, wherein the six primarycolor light beams are directed to a set of six digital micromirrordevice imagers and wherein each of the digital micromirror deviceimagers of the set of six digital mirror device imagers is configured toreceive a single primary color light beam of the six primary color lightbeams.
 3. The projection system according to claim 2, wherein the set ofsix digital micromirror device imagers is configured to project only adiscrete portion of an entire frame of a motion. picture image onto adisplay surface.
 4. The projection system according to claim 2, furthercomprising: a plurality of sets of six digital micromirror deviceimagers; wherein each set of six digital micromirror device imagers isconfigured to display an equal area of an entire frame of a motionpicture image onto a display surface.
 5. The projection system accordingto claim 1, wherein each digital micromirror device imager has aresolution of about 2K×1K.
 6. The projection system according to claim1, further comprising: a total internal reflection lens opticallydisposed between the light source and at least one of the digitalmicromirror device imagers.
 7. The projection system according to claim6, further comprising: a projection optics system optically disposedbetween the at least one total internal reflection lens and a displaysurface.
 8. The projection system according to claim 1, furthercomprising: a plurality of light beam splitting prisms for splitting thelight emitted from the light source into a plurality of separate beamsof light.
 9. The projection system according to claim 8, wherein each ofthe separate beams of light is directed to a different set of sixdigital micromirror device imagers.
 10. The projection system accordingto claim 8, wherein each of a plurality of sets of six digitalmicromirror device imagers is adapted to receive a single beam of lightof the plurality of separate beams of light.
 11. The projection systemaccording to claim 8, wherein each of a plurality of sets of six digitalmicromirror device imagers manipulates a received beam of light to carrymotion picture image data corresponding to only a discrete portion of anentire motion picture image frame.
 12. The projection system accordingto claim 1, further comprising: a projection optics system opticallydisposed between the plurality of digital micromirror device imagers anda display surface.
 13. The projection system according to claim 12,further comprising: an arrangement of reflective prisms and opticalblocks optically disposed between the plurality of digital micromirrordevice imagers and the projection optics system.
 14. The projectionsystem according to claim 1, wherein the primary color light beams arecyan, blue, yellow, green, red, and magenta.
 15. The projection systemaccording to claim 1, wherein at least one prism of the prism assemblyis a 45 degreed dichroic.
 16. A projection system, comprising: a lightsource for generating and emitting light; a prism assembly forseparating the light into four or greater primary color light beams; aplurality of digital micromirror device imagers configured to receiveand reflect the primary color light beams.
 17. The projection systemaccording to claim 16, further comprising: a plurality of light beamsplitting prisms for splitting the light emitted from the light sourceinto a plurality of separate beams of light.
 18. The projection systemaccording to claim 16, wherein each of the separate beams of light isdirected to a different set of digital micromirror device imagers, eachdifferent set having the same number of digital micromirror deviceimagers as there are primary color light beams.
 19. The projectionsystem according to claim 16, wherein each of a plurality of sets ofdigital micromirror device imagers is adapted to receive a single beamof light of the plurality of separate beams of light, each of theplurality of sets having the same number of digital micromirror deviceimagers as there are primary color light beams.
 20. The projectionsystem according to claim 16, wherein each of a plurality of sets ofdigital micromirror device imagers manipulates a received beam of lightto carry motion picture image data corresponding to only a discreteportion of an entire motion picture image frame, each of the pluralityof sets having the same number of digital micromirror device imagers asthere are primary color light beams.